Instance Segmentation

Computer Vision (CV) is a scientific field that researches software systems trained to extract information from visual data, analyze it, and draw conclusions based on the analysis. The area consists of so-called CV or vision AI tasks. Each task is unique and incorporates techniques and heuristics for acquiring, processing, analyzing, understanding the data, and extracting various details from it. One of these tasks is Instance Segmentation. On this page, we will:

  • Understand the basics of the Image Segmentation field in Machine Learning;

  • Cover in-depth the Instance Segmentation vision AI task;

  • See how Instance Segmentation compares with Semantic and Panoptic Segmentation;

  • Research the real-life applications of Instance Segmentation;

  • Cover some popular Instance Segmentation datasets and SOTA results on them;

  • See features that Hasty offers for streamlining an Instance Segmentation task.

Let’s jump in.

It is essential to start with a bigger picture. The logical question is, what is Image Segmentation in Machine Learning?

Well, Segmentation is a well-known term in business and marketing. In short, it defines the process of splitting customers (or a whole market) into separate groups based on specific patterns in their behavior. Fortunately, such a definition is close to what we refer to when saying Image Segmentation in ML.

Image Segmentation in Machine Learning is a part of the vision AI field that incorporates different methods of dividing visual data (for example, an image) into segments featuring specific, similar, and significant information of the same class label.

For example, if you have a picture from your prom, you can use Image Segmentation to find each person on an image and locate his boundaries.
Example of a segmentation map
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As of today, corporate Data Science regularly solves Image Segmentation challenges in various spheres. In Hasty, we see that the demand for high-quality Segmentation solutions has rapidly grown over the past couple of years. It also applies to Data Scientists who specialize in the Image Segmentation field. As a result, the industry is developing and growing, bringing new SOTAs, solution techniques, and challenges.

Nowadays, researchers say that the Image Segmentation field consists of three vision AI tasks. These are:

Let’s take a closer look at the Instance Segmentation vision AI task.

Moving from the bigger picture to the details, let’s see what Instance Segmentation is.

Instance Segmentation is a Computer Vision task that combines the ideas behind Object Detection and Semantic Segmentation tasks bringing a way more holistic output format. As you might know, Object Detection focuses on localizing the position of an object in an image (via a bounding box) and classifying it. On the other hand, Semantic Segmentation is about classifying every pixel in a picture to create a pixel-perfect segmentation map for a specific image.

As a combination, you get Instance Segmentation that detects all distinct objects in an image, segments them, produces a pixel-perfect segmentation mask for each object, and classifies them. Here is a simple example of how an Instance Segmentation model output might look like:

Example
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As a result, you get a task that can be used to tell one instance of a specific class from another and count them. If you have an instance ‘person’ class, an algorithm will mark each person on an image as a separate ‘person’ class instance (like ‘person1’, ‘person2’, etc.).

The data annotation process for an Instance Segmentation task is as follows:

  1. You predefine some instance target classes (for example, ‘person’ and ‘bicycle’);

  2. You create a segmentation mask for each distinct instance of the target classes.

To summarize, Instance Segmentation receives an image and some instance target classes as input. As an output, you get a bounding box, a segmentation mask, and the class for each instance of target classes.

Although Instance and Semantic Segmentation live in the same Image Segmentation field and share some similarities, they are still different vision AI tasks. You must remember it when identifying which task you aim to solve.

Semantic Segmentation classifies every pixel on an image, so all instances of the same category share the same class label. As a result, you get a segmentation map.

On the other hand, Instance Segmentation ensures that all the objects of the same class are viewed as distinct instances. So, from an IS model, you get a bounding box and a segmentation mask for each object.

Please consider the following question if you are unsure whether you should use Instance or Semantic Segmentation as your vision AI task. Do you want your model to be able to count distinct objects? If so, label data for an Instance Segmentation task. It is generally easy to use labels created for Instance Segmentation to solve a Semantic Segmentation task. However, the other way around is tricky. Please think carefully before rushing into the annotation process.

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To learn more about Semantic Segmentation, please refer to our Semantic Segmentation wiki page.

Although Panoptic and Instance Segmentation live in the same Image Segmentation field and share many similarities, they are still different vision AI tasks. You must remember it when identifying which task you aim to solve.

Instance Segmentation ensures that all the objects of the same class are viewed as distinct instances. So, from an IS model, you get a bounding box and a segmentation mask for each object.

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On the other hand, Panoptic Segmentation is a combination of Semantic and Instance Segmentation. In other words, with Panoptic Segmentation, you can obtain information such as the number of objects for every target class (countable objects), bounding boxes, segmentation masks, and a segmentation map of the whole image. These come from Instance Segmentation. However, you also get a segmentation map from Semantic Segmentation and know a target class for each pixel. So, Panoptic Segmentation provides a way more holistic understanding of a scene.

To learn more about Panoptic Segmentation, please refer to our definitive guide on Panoptic Segmentation.

Idea

Input

Output

Instance Segmentation

Find every distinct object of target classes

An image and some instance target classes

A bounding box and a segmentation mask for each instance of target classes

Semantic Segmentation

Classify every pixel on an image

An image and some semantic target classes

Pixel-perfect segmentation map of the whole image

Panoptic Segmentation

Combine Instance and Semantic Segmentation

An image and some instance and semantic target classes

Pixel-perfect segmentation map of the whole image

and

A bounding box and a segmentation mask for each instance of target classes

Nowadays, Image Segmentation is widely used across various industries. From our experience, it seems like Instance Segmentation is more popular than Panoptic and Semantic Segmentation. Still, it does not mean that Instance Segmentation holds the market, as there is always room for other tasks and approaches.

Please spend some time identifying the Computer Vision task that works the best for you, as switching tasks in the middle of the process might be costly time- and money-wise.

Here are some noteworthy Instance Segmentation applications:

  • Autonomous driving systems (for example, segmentation of visual input data from the camera - classification of a pedestrian on the road, a vehicle, signs, etc.);

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  • Medical data processing (for example, segmentation of MRI images searching for tissues, tumors, anomalies, and their characteristics such as area, dynamics, etc.);

  • Aerial, satellite, and UAV image processing (for example, segmentation of a landscape);

  • Video surveillance systems;

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  • And many other use cases.

Speaking about Instance Segmentation datasets and SOTA solutions, it is worth mentioning that many Image Segmentation datasets have Instance Segmentation annotations within their labels. Moreover, for the major part of them, Instance Segmentation is the primary focus.

This means that there are many trustworthy benchmark datasets regularly used to evaluate recent Instance Segmentation model architectures and approaches. The most popular ones are:

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Overall, many free or open-source Instance Segmentation datasets are available throughout the Web. Check out our review of 6 popular Instance Segmentation datasets to get started.

As you might know, data annotation might be a bottleneck for AI startups as the conventional labeling approach is both costly and time-consuming. Hasty’s data-centric ML platform addresses the pain and automates 90% of the work needed to build and optimize your dataset for the most​ advanced use cases ​ with our self-learning assistants using AI to train AI.

The primary focus of Hasty is the Computer Vision field. Therefore, Hasty is a perfect Instance Segmentation annotation tool as it implements all the necessary instruments to help you with your Instance Segmentation task.

Let’s go through the available options step-by-step. To streamline your Instance Segmentation annotation experience, Hasty offers:

As for the annotation quality control process, Hasty has you covered with its AI Consensus Scoring feature that has a separate Instance Segmentation review option. With the help of AI CS, you can find missing labels, extra labels, and different artefacts. Also, you will better understand how a machine sees your data, which might be valuable for your annotation strategy.

When it comes to model building, Hasty’s Model Playground supports many modern neural network architectures. For Instance Segmentation, these are:

As a backbone for these architectures, Hasty offers:

As a Machine Learning metric for the Semantic Segmentation case, Hasty implements mask mean Average Precision (mask mAP).

Hasty also has a Youtube channel featuring video tutorials for each vision AI task. Here is one about Instance Segmentation.

As of today, these are the key options Hasty has for the Instance Segmentation cases. If you want a more detailed overview, please check out the further resources or book a demo to get deeper into Hasty with our help.

Last updated on Jan 23, 2023

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